Abstract: The problem of the ocean tide effect on satellite gravity is discussed. The basic theory is introduced firstly. And then two global ocean tide models are used to estimate the loading effect up to harmonic degree 60, and the difference of the two ocean tide models is considered as the error estimation. The comparison between the numerical results and the standard deviation of gravity recovered with GRACE shows that the effect of ocean tide on satellite gravity is more serious than the error of the GRACE below degree 40. Although the accuracy of ocean tide models are improved with development of satellite altimetry, the current ocean tide models are not accurate enough for ocean tide correction to the GRACE below degree 12. Additionally, the effect of the local ocean tide in the vicinity of China is also investigated using tidal data of the East and South China seas and global model of FES02. The result shows that this effect is comparable with that of the current global ocean tide model error. This indicates the uncertainty of the current ocean tide model. Therefore, the accuracy of ocean tide correction to satellite gravity will be improved by combining more local tide data obtained with tide gauge observations.